Project Summary NIAAA identifies first-year college students as a high-risk group for heavy drinking and harmful consequences. Further, these students' perceptions of their peers' drinking (descriptive norms) are strong predictors of their own alcohol use and those norms are consistently misperceived; students overestimate peer drinking behavior, leading them to drink more themselves. Most universities require incoming students to complete remotely- delivered interventions to correct these misperceptions, known as Normative Re-education programs. However, the main risk-reduction approach in these programs, personalized normative feedback (PNF), suffers from limitations that have impeded large reductions in student alcohol use and consequences. Our pilot work has introduced a new smartphone-based app called CampusGANDR that delivers PNF within a weekly game about college life. During the game students submit questions, vote on their favorite questions, answer these questions, and win or lose points based on the accuracy of their responses. A major innovation of CampusGANDR is that it draws on recent literature in the field of gamification, adding features like points, leader boards, and chance-based uncertainty to make PNF more interesting, believable, and palatable to students. Further, we have successfully invited students to play the game voluntarily, rather than offering monetary compensation for taking part or making participation mandatory like most current programs and research initiatives. In the context of CampusGANDR students view feedback because they are intrinsically motivated, rather than extrinsically motivated, to do so. Based on extensive pilot work, the current proposal seeks to: 1) evaluate the efficacy of CampusGANDR in a large-scale multi-site trial; 2) identify the optimal dosage of alcohol feedback to deliver within CampusGANDR for correcting norms and reducing alcohol use among students who differ in alcohol use (non-drinkers, light to moderate drinkers, and heavy drinkers); 3) examine person-level moderators of intervention efficacy; and 4) evaluate the sustainability of CampusGANDR among students who use the app but aren't recruited into the study. During the first year of the project we will work with an award-winning app development company to design and program a fully-functional versions of the CampusGANDR app. Next, 2,400 first-year students will be recruited across three cohorts at two distinctly different campuses (Loyola Marymount University and the University of Houston) to play CampusGANDR for 12 weeks and to complete 4 surveys about their alcohol use and personality variables. Students who are not sampled into the survey study will still be able to take part in CampusGANDR, and their app usage data will be employed to measure the organic churn rate and viral growth coefficient of the app. The project will result in cutting-edge native smartphone (IOS, Android) and web-versions of the app able to dynamically tailor the dosage of alcohol feedback delivered based on students' alcohol experience at the point of matriculation.